I recently stumbled into DBX decoders by accidentally buying a DBX encoded record. I suppose we would call them HD Vinyl now. When I found a DBX NX-40 on ebay for $25, I thought it was worth an experiment. I normally run the turntable directly into the phono input of a McIntosh C49, so I thought I could run the signal from two spare RCA outputs to the NX-40 input labled "From RCVR Tape Output" and then from the its output labled "To RCVR Tape Input" another two cables to spare RCA inputs on the preamp. This seems to be what the instructions require to play a "disc" (by which is meant a record); however, turn the unit on, push "DBX disc decoder," and - no sound. Does anyone have any expereince with these decoders and the basic wiring set up? I can't tell whether I have a bad unit or I've somehow set it up wrong.
DBX NX-40 Setup
- Thread starter pderousse
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Blue Shadow
Waiting for Vintage Gear from this century
This dbx unit is designed to be used in a tape loop. Tape output to dbx and dbx output to tape input. A loop since it just processes the signal and the pre 'monitors' that signal as if you were listening to the tape just recorded.
Does the pre have a processor loop? I see it does not have tape monitor functions.
A trial method would be pre outputs to dbx and its output to amp but this isn't ideal using sometimes very low input to dbx when listening low volume.
Does amp have RCA inputs? Does amp have input level control?
Does the pre have a processor loop? I see it does not have tape monitor functions.
A trial method would be pre outputs to dbx and its output to amp but this isn't ideal using sometimes very low input to dbx when listening low volume.
Does amp have RCA inputs? Does amp have input level control?
The supplied schematic shows the unit sitting between a receiver and a tape recorder, so it has 8 RCA I/Os, 4 labeled "Receiver" and 4 labled "Tape Recorder." I suppose we are saying the same thing. To play a disk it states "check that the receiver is set to tape monitor. Push in the DBX Disk Decoder on the NX40 and play the record." I interpreted this to mean that the pre outputs to the DBX and listens to the DBX input, the tape loop of which you write. All of the I/Os on the C49 can be user labled and trimmed, but it sounds like you are saying there's no way to set the C49 to operate two open inputs at once (phono and DBX) - the tape monitor in other systems. I don't want to rig a plug this into the amp, which only has XLR. Sorry for the noob questions, I've never used this thing. It helps to talk my way through this.
Blue Shadow
Waiting for Vintage Gear from this century
The unit does not need a tape deck to work. Those are on it to replace the tape loop on the receiver it uses up. Common for signal processors to replicate the tape loop, eqs have em as do other items of their ilk.
I do not know if the C49 can be on phono and have the signal leave and come back for processing and then go to the amp outputs. It doesn't look possible with the rear panel connections all appear one way, ins or outs and no loops.
That is why I said to try it, if you can connect it between the c49 output to the amp input. Not ideal but an opportunity to try it. dbx noise reduction is pretty special, unfortunately it came around right about the time the CD was becoming known and only about 220 titles were made with dbx processing.
To be sure the c49 will not do a processor loop, you could ask on the McIntosh forum. Those guys know that gear.
I do not know if the C49 can be on phono and have the signal leave and come back for processing and then go to the amp outputs. It doesn't look possible with the rear panel connections all appear one way, ins or outs and no loops.
That is why I said to try it, if you can connect it between the c49 output to the amp input. Not ideal but an opportunity to try it. dbx noise reduction is pretty special, unfortunately it came around right about the time the CD was becoming known and only about 220 titles were made with dbx processing.
To be sure the c49 will not do a processor loop, you could ask on the McIntosh forum. Those guys know that gear.
